From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0756CC388F9 for ; Tue, 27 Oct 2020 16:51:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B7BF122258 for ; Tue, 27 Oct 2020 16:51:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1813538AbgJ0Quw (ORCPT ); Tue, 27 Oct 2020 12:50:52 -0400 Received: from smtprelay0035.hostedemail.com ([216.40.44.35]:33548 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1813523AbgJ0Quu (ORCPT ); Tue, 27 Oct 2020 12:50:50 -0400 Received: from filter.hostedemail.com (clb03-v110.bra.tucows.net [216.40.38.60]) by smtprelay04.hostedemail.com (Postfix) with ESMTP id 86139180A7FE0; Tue, 27 Oct 2020 16:50:43 +0000 (UTC) X-Session-Marker: 6A6F6540706572636865732E636F6D X-HE-Tag: bag02_2a11e012727d X-Filterd-Recvd-Size: 4083 Received: from XPS-9350.home (unknown [47.151.133.149]) (Authenticated sender: joe@perches.com) by omf19.hostedemail.com (Postfix) with ESMTPA; Tue, 27 Oct 2020 16:50:38 +0000 (UTC) Message-ID: <685d850347a1191bba8ba7766fc409b140d18f03.camel@perches.com> Subject: Re: [PATCH 3/8] vhost: vringh: use krealloc_array() From: Joe Perches To: "Michael S. Tsirkin" , Bartosz Golaszewski Cc: Andy Shevchenko , Sumit Semwal , Gustavo Padovan , Christian =?ISO-8859-1?Q?K=F6nig?= , Mauro Carvalho Chehab , Borislav Petkov , Tony Luck , James Morse , Robert Richter , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Daniel Vetter , Alexander Shishkin , Linus Walleij , Jason Wang , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , Jaroslav Kysela , Takashi Iwai , linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, linux-kernel@vger.kernel.org, linux-edac@vger.kernel.org, linux-gpio@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-mm@kvack.org, alsa-devel@alsa-project.org, Bartosz Golaszewski Date: Tue, 27 Oct 2020 09:50:36 -0700 In-Reply-To: <20201027112607-mutt-send-email-mst@kernel.org> References: <20201027121725.24660-1-brgl@bgdev.pl> <20201027121725.24660-4-brgl@bgdev.pl> <20201027112607-mutt-send-email-mst@kernel.org> Content-Type: text/plain; charset="ISO-8859-1" User-Agent: Evolution 3.38.1-1 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-edac@vger.kernel.org On Tue, 2020-10-27 at 11:28 -0400, Michael S. Tsirkin wrote: > On Tue, Oct 27, 2020 at 01:17:20PM +0100, Bartosz Golaszewski wrote: > > From: Bartosz Golaszewski > > > > Use the helper that checks for overflows internally instead of manually > > calculating the size of the new array. > > > > Signed-off-by: Bartosz Golaszewski > > No problem with the patch, it does introduce some symmetry in the code. Perhaps more symmetry by using kmemdup --- drivers/vhost/vringh.c | 23 ++++++++++------------- 1 file changed, 10 insertions(+), 13 deletions(-) diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c index 8bd8b403f087..99222a3651cd 100644 --- a/drivers/vhost/vringh.c +++ b/drivers/vhost/vringh.c @@ -191,26 +191,23 @@ static int move_to_indirect(const struct vringh *vrh, static int resize_iovec(struct vringh_kiov *iov, gfp_t gfp) { struct kvec *new; - unsigned int flag, new_num = (iov->max_num & ~VRINGH_IOV_ALLOCATED) * 2; + size_t new_num = (iov->max_num & ~VRINGH_IOV_ALLOCATED) * 2; + size_t size; if (new_num < 8) new_num = 8; - flag = (iov->max_num & VRINGH_IOV_ALLOCATED); - if (flag) - new = krealloc(iov->iov, new_num * sizeof(struct iovec), gfp); - else { - new = kmalloc_array(new_num, sizeof(struct iovec), gfp); - if (new) { - memcpy(new, iov->iov, - iov->max_num * sizeof(struct iovec)); - flag = VRINGH_IOV_ALLOCATED; - } - } + if (unlikely(check_mul_overflow(new_num, sizeof(struct iovec), &size))) + return -ENOMEM; + + if (iov->max_num & VRINGH_IOV_ALLOCATED) + new = krealloc(iov->iov, size, gfp); + else + new = kmemdup(iov->iov, size, gfp); if (!new) return -ENOMEM; iov->iov = new; - iov->max_num = (new_num | flag); + iov->max_num = new_num | VRINGH_IOV_ALLOCATED; return 0; }